This book is about Evidence-based dentistry (EBD) is an approach to oral health care that requires that judicious integration of systemic assessments of clinically relevant scientific evidence relating to the patients oral and medical condition and history, with the dentist¿s clinical expertise and patient¿s treatment need and preferences. The purpose of EBD is to ¿close the gap between what is known and what is practiced.¿ The lack of systematic reviews from prospective well designed.clinical trials led to delays in incorporating and testing new information. These studies are focused providing the best evidence-based services.